Volume 111 OCTOBER, I'JUU PAUT'lTi 



THE EFFECT OF PARTIAL STERILISATION OF 

 SOIL ON THE PRODUCTION OF PLANT FOOD. 



By EDWARD JOHN RUSSELL, D.Sc. (Loncl), and 

 HENRY BROUGHAM HUTCHINSON, Ph.D. 



(Bothamsted Experiment Station.) 



Introduction. 



When soil is partially sterilised, either by heat or by volatile 

 antiseptics like carbon disulphide, toluene, etc., it becomes more pro- 

 ductive and capable of yielding larger crops. The effect of heat was 

 discovered incidentally about 2-5 years ago by the early soil bacteriolo- 

 gists ; the action of carbon disulphide was first noticed somewhat later 

 by a vine grower who had used it to kill phylloxera. Both cases have 

 since been studied by several investigators, notably Koch^ and Hiltner 

 and Stormer- ; a paper was also recently published by one of us* in 

 which it was shown that the property is a general one, holding for all 

 the soils and volatile antiseptics examined and for all the plants, 

 excepting those of the leguminous order. Thus when a soil had been 

 heated to 95° C. it produced two, three, or sometimes four times as 

 much crop as a portion of the soil which had not been heated, whilst 

 treatment with volatile antiseptics led to an increase in crop varying 

 between 20 and 50 per cent. The treatment had in some way brought 

 about a considerable increase in the amount of plant food — nitrogen, 

 phosphorus, and potassium — obtainable by the plant ; even more, 

 indeed, than might be expected from the weight of the crop, since there 

 was an increased percentage of nitrogen and phosphorus in the 

 material of plants grown on the treated soils. The results quoted in 



1 Koch, Arbeiten der deutschen Landwirtschaft-Geselhchaft, 1899, Heft 40. 



2 Hiltner and Stormer, Arbeiten der Biolog. Ahteilung f. Land- u. Forstwirtschaft, 

 1903, Bd. 3, Heft 5. 



^ Darbishire and Russell, Journal of Agricultural Science, 1908, Vol. ii. p. 305. Full 

 references to the literature of the subject are given in this paper. 



Journ. of Agric. Sci. iii 8 



